The Properties That TIMKEN Bearing Materials Should Have When Using Them

1. Friction compatibility
The performance of preventing adhesion and boundary lubrication when the shaft diameter is in direct contact with the bearing bush. The material factors that affect the friction compatibility of the friction pair are:
(1) The ease of metallurgically forming an alloy from the secondary materials.
(2) The affinity between the material and the lubricant.
(3) Friction factor of the paired materials in a non-lubricated state.
(4) Microstructure of materials.
(5) Thermal conductivity of materials.
(6) The size of the material surface energy and the characteristics of the oxide film.
2. Embeddedness
The ability of a material to allow the entrapment of foreign hard particles in the lubricant and prevent scratching and/or abrasive wear. For metal materials, those with low hardness and low elastic modulus have good embedding properties, while non-metallic materials may not necessarily have good embedding properties. For example, carbon graphite has a low elastic modulus but poor embedding properties. Sliding bearings usually use softer materials and harder materials to form the friction width, and softer materials are generally used as bearing bushes.
3. Running-in property
During the running-in process of the shaft diameter and the bearing bush, the ability to reduce the machining error, coaxiality error, and surface roughness parameter values of the shaft diameter and bearing bush to make the contact uniform, thereby reducing friction and wear rate.
4. Friction compliance
The material relies on the elastic-plastic deformation of the surface layer to compensate for the poor initial fit of the sliding friction surface and the deflection performance of the shaft. Materials with low elastic modulus have better compliance.
5. Wear resistance
The ability of a pair of materials to resist wear. Under specified wear conditions, the wear resistance is expressed by the reciprocal of the wear rate, wear degree, and wear amount.
6. Fatigue resistance
The ability of a material to resist fatigue damage under cyclic loading. At the service temperature, the strength, hardness, impact strength and structural uniformity of the bearing material are very important for fatigue resistance. Materials with good running-in and embedding properties usually have poor fatigue resistance.
7.Corrosion resistance
The ability of a material to resist corrosion. Lubricating oil will gradually oxidize and produce acidic substances when used in the atmosphere. Most lubricating oils also contain extreme pressure additives, which will corrode bearing materials. Therefore, bearing materials need to be corrosion-resistant.
8.Cavitation resistance
When the solid moves relative to the liquid, when the bubbles in the liquid burst near the solid surface, local impact high pressure or local high temperature is generated, which will lead to cavitation wear. The ability of a material to resist cavitation wear is called cavitation resistance. Generally, copper-lead alloys, tin-based bearing alloys and aluminum-zinc-silicon alloys have better cavitation corrosion resistance.
9. Compressive strength
The ability to withstand unidirectional loads without being crushed or changing in size.